For those that have frequented this forum, and, in particular, read the MPG threads where I posted about my unusually low gas mileage, I was finally validated yesterday!

Background:
My car is a 2010 VW GTI DSG. EPA estimates for gas mileage are 24 City / 32 Hwy. From day 1, I noticed the gas mileage didn't measure up and seemed unusally poor for this car, given my last car, a 2007 Audi A4 Avant 2.0T manual had better mileage even with AWD and it weighed ~400 lbs more! Over the first couple months of ownership, I could not get better than 26 MPG hwy and around 21 City, combined 23-24 per fill-up. No, I'm not chipped, and no I don't have a lead foot, as has been asked of me several times. Oh, and the sooty tail pipes were also a HUGE visual indicator this car was running rich.

Anyway, after two failed attempts to find anything during my 90 day inspection and a 5k oil change (I know, it is not recommended), I was hesitant to even bring it up again, but when the service advisor asked "is there anything else we can do while your car is in for the 10k service?", I decided to give it another try, telling her of my MPG woes.

Third time's the Charm:
During my 10k service yesterday, the VW technician performed a TSB for the throttlebody control that affected my VIN. Well, looking into the problem more he saw on the VAG-COM that when my throttlebody was opened 71%, the car was dumping 100% fuel! For reference, this percentage should be closer to 90% when fuel is at 100%. Looking into the situation further revealed other poor settings.

The technician did the TSB to the throttlebody and made some VAG-COM adjustments. He did a couple test drives to see the effect and confirm things had actually improved. Imagine that?

All this was explained to me in great detail and I could tell the techncian was a determined individual to trouble shoot this problem and communicated it to me, properly. I was impressed. All that I experienced and all that he said was logical and made sense.

The Proof:
Driving home, about a 25 mile drive, I noticed the MPGs did improve. My avg when I exited the hwy was well over 30 MPGs! Since then, I have been watching the consumption and the tail pipes. All seems to be much improved. On my drive into work this morning, driving as I normally do in rush hour, I got my best Avg MPG yet, almost 34 MPG! Before this, I could barely reach 30 MPG on the computer readout (which we all know is a bit optimistic).

Glad you had it documented! Running that rich, that long, will have an effect on your catalytic converter.
Watch for any sound or performance changes in the near future or ask the tech that actually found the problem about it.

I wonder if I'm having the same issues. In town on the way to work I get 30mpg but on our last trip hwy driving with cruise control on I could barely get 26mpg. My 10k service is almost here so I'll have them check it out.

Glad you had it documented! Running that rich, that long, will have an effect on your catalytic converter.
Watch for any sound or performance changes in the near future or ask the tech that actually found the problem about it.

Thanks for the tip. I'll keep this in mind and talk to the Technician about it.

I wonder if I have the same issue. I normally get 25 no matter how or where I drive. I took a 2 hour trip last weekend and was very aware of my driving, basically driving like a granny. I only pulled 27. My tailpipes are always black.

I'm stage 1, mileage has not gotten better or worse since the flash...

This is about a 1.5 to 2 MPG improvement, considering this was mostly city driving. Prior to this update, I would get about 24 MPG actual on a fill-up with the same commuting miles that are mostly City driving.

As for the carbon build-up around the tail pipes, still there, but it does seem like an improvement over what I used to see.

hmmmm thats interesting, my mpg is unusually low but I mostly do stop and go city driving but it should still be in the 24-25 range right. I've been thinking and I'm completely stock and I don't have a lead foot, maybe same issue?

I just brought mine in for the 90 day inspection. They actually brought the update to my attention. I asked the service guy what was it for and he simply read back, "body control module," off of the sheet to me. I'm pretty sure he didn't know a jack about what it was for but whatever. Haven't flashed my ECU so I was like why not?

Brought it in with half a tank in the car so I'll find out in about a week if it did the trick. I've been averaging 23-24 mpg combined (26 on highway and ~21-22 in the city).